Art of treating vegetable fibers



Patented Oct. 22, 1935 ART or TREATING VEGETABLE FIBERS Ralph H. McKee, Jersey City, and Earle H. Morse,

Nutley, N. J.

No Drawing. Application July 10, 1930,

Serial No. 467,127

8 Claims.

The present invention relates to the art of treating vegetables fibers and more particularly to a process of treating' a vegetable fiber to convert the same into a fiber resembling wool and to the product of such process.

It is an object of the present invention to provide an improved process for treating an inexpensive fiber such as jute, hemp, mallow, etc., in such a manner as to convert the same into a fiber resembling, and having largely the properties of ordinary wool.

It is another object of the invention to provide an improved process by the use of which an improved product having a quality and color better than heretoforeobtainable is produced.

It is a further object of the invention to provide an improved process of treating fibers whereby the quantities of reagents used for converting inexpensive fibers. into wool-like fibers are materially decreased.

A still further object of the invention is to control the loss of weight of the inexpensive fiber such as juteor the like by regulating the conditions of treatment. Our invention provides a process by which the loss of weight'of the vegetable fibers, i. e.. the amount of non-cellulosic components left in the fiber, can be controlled by controlling the factors of the initial treatment I thus possible to economize materially on the consumption of caustic soda in the crinkling bath.

Broadly stated we have discovered that we can improve the process of converting vegetable fibers into fibers of wool type and obtain an improved product by subjecting jute and similar fibers to (1) an initial oxidation and hydrolysis treatment, (II) a crinkling treatment and (III) a. bleaching treatment.

We base the present invention on the fact that the yellow color obtained when jute is treated with an alkali is due to neither the cellulose nor the lignin but to another type of compound, perhapsa glucoside, which contains within it, or has mixed with it an oxygen type of dye color. In fact, there is, apparently,' more than one such coloring material. These dyes are nearlycolorless when in neutral or acid solution but in thepresence of alkali, become colored (wellows and browns) and at the same time tend to fix themselves to the fiber. Accordingly, we remove these materials, leaving, asnearly as possible, only cellulose and lignin, and we accomplish this removal under conditions which are approximately neu- 10 tral (i. e. a pH value of about 5 to about 9) but in no case strongly alkaline. Of course after we have washed out these coloring materials, we can without permanently 15 use a strong caustic soda discoloring the fiber.

We accomplish-removal of the coloring materials by oxidizing and hydrolyzing them in a neutral or slightly acid solution and washing out the resultant products; In practice we find it best to carry out this process with a pH of 5 to 90 approximately 8.

A specific example is given for purposes of iilustration but it isto be understood that none 01 the specific substances, temperatures, concentrations or the like are be taken as limitations 35 upon the invention.

Other objects and advantages of the invention will become apparent from the following description of a typical run of this process. Jute fibers are preferably, but not necessarily, cut into lengths as desired (say about 5") and are opened up by means of a "card .or picker in order that the solutions employed in the treatment of the fibers can easily and thoroughly pentrate to the individual fibers.

After the fibers are cut and opened they are preferably washed to remove adhering foreign matter, such as dust, dirt and water soluble materiais associated therewith. This washing is, however, not essential. In carrying out this operation, we prefer to add a small amount of sulfonated oil, such as "Monopole or. "Turkey red" oil, to the water with which the washing is effected. Any excess 01 sulfonated oil is removed by rinsing with fresh water, either hot or cold, before the fiber is given the initial oxidation treatment. .The washing operation, in addition to removing foreign matter, wets out the fibers in such a manner that a uniform and thorough action can be obtained during subsequent treatments with chemicahreagents.

Step. I when the jute fibers have been prepared as described hereinabove they are ready for the a priate manner.

initial oxidation treatment. A nearly neutral solution which simultaneously gives some hydrolysis is used. In practice, we prefer to efiect this treatment in a solution which has been buffered so that the pH has a value of about 6 to 8.

A typical bath for this step may be made up as follows:

Potassium permanganate v Spounds Tri-sodiumphosphate 14 pounds Phosphoric acid (85%) 3pounds- Water 3500 gallons Such an oxidizing bath is capable of treating about 1000 pounds of jute. A temperature of about 25 C. (about room temperature) is suitable for this step. At this temperature a period of about 15 to minutes in theoxidizing bath is required.

During this oxidizing treatment some manganese dioxideis precipitated on the -iute fibers. This precipitate can be removed in any appro- For instance, we may first press out the excess of liquid and then treat the jute temperature of approximately 60 C.

' dation, and hydrolysis occur simultaneously may be used insteadof the above series. Such a bath may consist of Monopole oil; 30 pounds Tri-sodlum phosphate-- 20 pounds Phosphoric acid (85%).. 9.3 pounds Hydrogen peroxide (100 volume) 10 poundsor more Water 3500 gallons In this case temperatures up to; C. may be used and 20 minutes is then a sufiicient time. There is no precipitated manganese dioxide, of course, in this bath and therefore no acid sodium sulflte is required.

step 1i The fibers are now ready for their alkali treatment. This may be carried out in two stages. In the first stage the fibers are given a preliminarytr'eatment in a bath of very dilute-caustic soda (about 0.1%) at a temperature of about C. to about 80 C. At this temperature a treatment for about an hour has been found suiilcient to remove the desired amount of noncellulosic components such as lignin. By increasing the causticstrength larger amounts of noncellulosic materials may be removed and-by controlling causticcontent, temperature, time, etc.) the loss of weight may be varied from about 5% to as high as 30%"or more. The quality and character of the finished product vary with the loss of weight as will be readily understood. In practice, we prefer to operate limiting; the loss to 5 to 10% in the weight of the fiber. Before proceeding with the second stage I of alkali treatment the excess of dilute caustic solution is pressed from the fibers," e. g., by passing them through rolls. The pressed 'fi bers are then treated in a second caustic soda bath whichisofsuchastrengtb,that,together with the water present in the fibers, the resulting solution will preferably have approximately a 10% caustic soda content. with a solution of this'character a few minutes, say ten minutes. I

in the bath is ample time of contact.

In commercial practice the strength of the second caustic soda bath is determined by the amount of crinkle desired in the flnishedfiber. Solutions having a causticrsoda content lower 1 than 10% canbeusedinthesecond stage ofthe alkaline treatments although we prefer to use a solution having a caustic soda content of about 10% or somewhat higher. As a general rule, the stronger the caustic soda bath or the lower the is temperature thereof, the more crinkle is produced in the finished fibers.

The same result may be accomplished, but at a sacrifice of caustic soda, by using only a single bath of the strength of the second, or crinkling. bath. A longer time in the strong alkali both may then be .needed.

After the fibers have been subjected tothe strong alkali treatment they are washed thoroughly to free them from alkali. This'is pref- 2 erably accomplished by a series of washings. The last washing bath may desirably contain a small amount of an acid such as phosphoric acid or an acid salt of phosphoric acid such as monosodium phosphate ,(NaHzPOd or other acid salts 30 of similar character. A. washing. bath ofthis character insures the complete neutralization of alkali contained in or adsorbed on the fibers.

I Step III The washed, crinkled fibers are then ready for bleaching and softening. The said fibers have a brown color at this stage of the process but this brown color is of such a character as to be 40 easily removable by the succeeding bleaching operation.

The bleaching may be accomplished. with a. variety of solutions, for instance, solutions containing a permanganate or hydrogen peroxide or 4.5,,

perborates, or similar bleaching agents. In practice, we have found that excellent results are obtained when the bleaching solution has a pH value of less than about 8. Under some conditions, it has been found best to bleach in a series 6 of solutions using the same or difierent bleaching agents in each solution. Bleaching in stages usucrinkled fibers are immersed in a solution con- 1 tainlng about 0.1% by weight of hydrogen peroxide (H201) which has been buffered by means of sodium-phosphate and phosphoric acid to give a pH value of about'8. An amount of sulfonated oil equal to about 1% of the weight of the fiber is added to the bath to insure wetting of the fibers. The sulfonatedoil, althoughnot essential, facili tates the bleaching and is an aid to uniformity of the product. The fibers aremaintained in the bath about 16 hours, the exact time depending on the temperature and shade desired in the finished product. The excess of bleaching solution. is removed by passing the fibers through rolls or the like orby washing or both. The second stage of the bleaching operation-inmanganese dioxide is precipitated on the fibers in the aforesaid bleaching operation and is reabout 0.01% of oxalic acid. Of course, other acids having properties similar in this respect to oxalic acid can also be employed, for example, hydrochloric acid. If treated with oxalic acid or the like, the fibers must be washed free of this acid preparatory to the subsequent operations.

The washed; bleached. and crinkled fibers now resemble wool fibers. To give them the desired softness, they are treated with any of the well known softening materials commonly used for this purpose in the textile industry, for instance, materials such as soaps, suli'onated oils, glycerine and the like may be employed. After softening and drying. the fibersare ready for use as an article of commerce. These fibers can be carded and spun in the same 'way as natural wool fibers can be carded and spun. The converted fibers can be used alone or mixed with natural wool for the production of a great variety of articles and materials, including textile fabrics, rugs, blankets and the like as one skilled in the art will readily understand.

In the present specification and claims when the term oxid zing is used, it is to be understood to mean a treat'ment with an agent giving oxygen directly as, for example, potassium permanganate, hydroe'en peroxide, sodium perborate, etc. The term oxidizing as used herein does not refer to treatment with such agents as, for example, sodium hypochlorite. which in the alkaline condition is both an oxidizing agent and a chlorinating agent for .iute and similar fibers and in acid solutions is primarily a chlorinating agent.

We claim:

1. The process of treating vegetable fibers to convert the same into fibers resembling natural wool which comprises subjecting the vegetable fibers to oxidizing treatment at a pH between 5 and 8, then crinkling the thus treated fibers by subjecting them to the action of a caustic soda solution of approximately strength.

2. The process of treating vegetable fibers to convert the same into fibers resembling natural wool which comprises subjecting the vegetable fibers to an oxidizing hath having a pH of about 5 to approximately 8, then crinkling the thus treated fibers by subjectirg them to the action of a caustic soda solution of approximately 10% strength and finally bleaching said fibers.

3. The process of treating vegetable fibers to convert the same into fibers resembling naturalwool which comprises subjecting the vegetable fibers to an initial oxidizing and hydrolyzing treatment at a pH of about 5 to about approximately 8, then crinkling the thus treated fibers 5 i by subjecting them to the action of a caustic soda solution of approximately 10% strength and finally bleaching said fibers.

4. The process or treating vegetable fibers to convert the same into fibers resembling natural 10 wool which comprises treating the fibers with an aqueous bath containing a small amount of sulfonated oil, subjecting the vegetable fibers to an oxidizing and hydrolyzing treatment at a pH of about 5 to approximately 8, then crinkling the thus treated fibers by subjecting them to the action of a caustic soda solution of approximately 10% strength and finally bleaching said fibers.

5. Thev process of treating vegetable fibers to convert the same into fibers resembling natural wool which comprises washing the fibers, wetting the washed fibers with an aqueous vehicle containing a suli'onated oil, subjecting said thus treated fibers to an oxidation treatment in an approximately neutrai solution, washing said fibers with water, crinkling said fibers by contacting them with caustic soda solution of about 10% strength, washing said fibers tree of caustic, and bleaching said crinkled fibers by subjecting them to the action of a bleaching solution having a pH to value 01 less than about 8.

6. The process of treating fibers of the jute type which comprises cutting'said fibers into short lengths, opening up said fibers to permit penetration by the solutions, washing said out fibers, rinsing said washed fibers with water, immersing about 1000 parts 01 said fibers in a bath containing about 30 parts of sultonated. oil. 20 parts of trisodium phosphate, 9.3 parts phosphoric acid (85%) about 10 parts hydrogen peroxide, and 40 about 30,000 parts of water, washing the fibers with water to free them of the aioresaid bath, treating the washed fibers with a caustic soda solution of about 10% strength to give the desired amount of crinkling, washing the crinkled fibers free oi alkali. and bleaching the said fibers with a bleaching solution having a pH value 01' less than about 8. v

7. The process of treating fibers of the jute type which comprises cutting said fibers into'short lengths, opening up said fibers to permit penetration by solutions, washing said out fibers, rinsing said washed fibers with water, immersing about 1,000 parts of said fibers in a bath containing about 30 parts 01' suli'onatedoil, 20 parts of trisodium phosphate, 013 parts of phosphoric acid (85%), about 10 parts of hydrogen peroxide and about 30,000 parts of water, washing the fibers with water to free them of the aforesaid bath. treating the washed fibers with a caustic soda solution of about 10% strength to give the desired amount of crinkling, washing the alkali from the crinkled fibers, and bleaching the said fibers with a bleaching solution having a pH penetration of the solutions, immersing about 1,000 parts of said fibers in a bath containing about 30 parts of sulfonated oil, 20 parts or trisodium phosphate, 9.3 parts of phosphoric acid II muhm mpmsornym emndema, themn mmr emddummmmmemm about 30,000 parts of water, washing the fibers weightottheflberstmmaboutw toabout30%. wlthwa'tertotreethemoftheatoremdbatk. washingthe crlnk1edflbers.1'ree o1 alkal1,and trestlngflaewaahedflberswith a causflcaoda aobleacmnz the said fibers with a bleaching so1u-' luflnnotabout10%sumathtoproducethedetlonhavingapfivglueotleasthanabout8.

sized mum at crlnkllng, controlling the afore- RALPH H. mm. 3 saidtreatment including thecwsticaodacontent, EAR-IE H. MORSE. 

